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| author | Christoph Hellwig <hch@lst.de> | 2020-09-28 08:51:08 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2020-09-28 08:51:08 -0700 |
| commit | c3d4ed1abecfcfc801199cfadb71f5b80e025d9e (patch) | |
| tree | e9c9f9b12f6161b19673284bfa80719a115d8b59 /fs/iomap | |
| parent | 4595a298d5563cf76c1d852970f162051fd1a7a6 (diff) | |
| download | linux-riscv-c3d4ed1abecfcfc801199cfadb71f5b80e025d9e.tar.gz linux-riscv-c3d4ed1abecfcfc801199cfadb71f5b80e025d9e.tar.bz2 linux-riscv-c3d4ed1abecfcfc801199cfadb71f5b80e025d9e.zip | |
iomap: Allow filesystem to call iomap_dio_complete without i_rwsem
This is to avoid the deadlock caused in btrfs because of O_DIRECT |
O_DSYNC.
Filesystems such as btrfs require i_rwsem while performing sync on a
file. iomap_dio_rw() is called under i_rw_sem. This leads to a
deadlock because of:
iomap_dio_complete()
generic_write_sync()
btrfs_sync_file()
Separate out iomap_dio_complete() from iomap_dio_rw(), so filesystems
can call iomap_dio_complete() after unlocking i_rwsem.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/iomap')
| -rw-r--r-- | fs/iomap/direct-io.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 024d4bb3028e..b005ef5f554e 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -76,7 +76,7 @@ static void iomap_dio_submit_bio(struct iomap_dio *dio, struct iomap *iomap, dio->submit.cookie = submit_bio(bio); } -static ssize_t iomap_dio_complete(struct iomap_dio *dio) +ssize_t iomap_dio_complete(struct iomap_dio *dio) { const struct iomap_dio_ops *dops = dio->dops; struct kiocb *iocb = dio->iocb; @@ -130,6 +130,7 @@ static ssize_t iomap_dio_complete(struct iomap_dio *dio) return ret; } +EXPORT_SYMBOL_GPL(iomap_dio_complete); static void iomap_dio_complete_work(struct work_struct *work) { @@ -416,8 +417,8 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, * Returns -ENOTBLK In case of a page invalidation invalidation failure for * writes. The callers needs to fall back to buffered I/O in this case. */ -ssize_t -iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, +struct iomap_dio * +__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, bool wait_for_completion) { @@ -431,14 +432,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, struct iomap_dio *dio; if (!count) - return 0; + return NULL; if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion)) - return -EIO; + return ERR_PTR(-EIO); dio = kmalloc(sizeof(*dio), GFP_KERNEL); if (!dio) - return -ENOMEM; + return ERR_PTR(-ENOMEM); dio->iocb = iocb; atomic_set(&dio->ref, 1); @@ -568,7 +569,7 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, dio->wait_for_completion = wait_for_completion; if (!atomic_dec_and_test(&dio->ref)) { if (!wait_for_completion) - return -EIOCBQUEUED; + return ERR_PTR(-EIOCBQUEUED); for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); @@ -584,10 +585,26 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, __set_current_state(TASK_RUNNING); } - return iomap_dio_complete(dio); + return dio; out_free_dio: kfree(dio); - return ret; + if (ret) + return ERR_PTR(ret); + return NULL; +} +EXPORT_SYMBOL_GPL(__iomap_dio_rw); + +ssize_t +iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, + const struct iomap_ops *ops, const struct iomap_dio_ops *dops, + bool wait_for_completion) +{ + struct iomap_dio *dio; + + dio = __iomap_dio_rw(iocb, iter, ops, dops, wait_for_completion); + if (IS_ERR_OR_NULL(dio)) + return PTR_ERR_OR_ZERO(dio); + return iomap_dio_complete(dio); } EXPORT_SYMBOL_GPL(iomap_dio_rw); |